Method of sealing cans



Nov. 24, 1931. J. M. MccLATcHIE METHOD OF SEALING CANS 7 Original Filed Aug. 3. 1928 BY ATTORNEY Patented Nov. 24, 1931 UNITED STATES PATENT OFFICE JOHN H. MCGLATCHIE, OF NEW YORK, N. Y., ASSIGNOR TO THE BORDEN COMPANY, 01' NEW YORK, N. Y., A. CORPORATION OF NEW JERSEY METHOD OF SEALING CANS Original application filed August 8, 1928, Serial No. 297,330. Divided and this application filed February 20, 1930. Serial No. 429,924.

The invention relates to an improvement in closures for cans and more particularly to an improvement in closures for cylindrical metal cans provided at one end with a filling hole through which the food or other product to be preserved is introduced 1nto the can and to an improved method of closing and sealing the hole and thereby hermetically sealing the can. The present application is a division of my co-pendmg application, Serial No. 297,330, filed August 3, 1928.

The invention deals more especially with the type of can in which the two ends or heads are secured or soldered to the cylindrical body portion, one of the heads, called the top, being provided with a round central hole which is closed and sealed after the food or other product has been introduced into the can through it. If the filling hole is small, as in the cans for containing evaporated niilk or the like, the closing and sealing of the hole is accomplished by means of a dab of melted solder. If the hole is too large to be closed by solder only, the hole is, in some cases, first closed by a metal cap, after which the joint between the cap and the edges of the hole is sealed with solder. In other cases the cap is swaged or overlapped with the edges of the hole in such fashion that no solder is necessary to establish a tight joint between them. These former methods of closing and sealing cans of this type are objectionable for one or more reasons: If the filling hole is small enough to be closed by a dab of solder, it is too small to permit any but the most liquid food or other material to be introduced rapidly into the can. If, on the other hand, the filling hole is large enough to admit the food or other material rapidly, the closing and sealing of the hole requires a lengthy operation or the use of expensive apparatus.

The object of the invention is twofold: First, to permit of the use of a filling hole of any desired size by which the can may be filled with the required rapidity; and second, to close and seal the hole, whatever its size, expeditiously and by the use of simple and inexpensive apparatus. To this end the invention consists in providing a depression around the filling hole in the top of the can into which is forced a piece of sheet metal slightly larger than the depression and cut from a sheet of metal supported in close proximity to the top of the can. Inasmuch as the closure is larger than the depression the act of forcing the closure into the depression crushes the edges of the closure and the adjacent walls of the depression and thereby establishes a tight joint between them. in order to prevent any outwardly acting pressure within the can from forcing the closure out of the depression, the means for forcing the closure into the depression acts upon the center of the outer face of the closure, thereby causing the closure to assume a convexo-concave shape as it is forced into the depression, the outer face of the closure being concave. The invention is more fully described hereinafter and is particularly pointed out in the appended claims.

The improved method of closing and sealing cans is illustrated in the accompanying drawings, in which Figs. 1 and 2 are, respectively, a top and a side elevation (partly in section) of the improved can. Figs. 3, 4: and 5 illustrate diagrammatically the various steps of cutting the closure and inserting it into the depression in the top of the can. And Fig. 6 is a diagrammatic view illustrating the application of solder to the joint between the closure and depression in the top of the can.

In its general features of construction the can sealed by the improved method may have any usual or preferred form, the can shown in the drawings comprising a cylindrical body portion 7 closed at its lower end or bottom by the head 8 and at its upper end or top by the head 9. The joints 10 between the heads 8 and 9 and the body portion are preferably filled with solder. In the center of the head or top end 9 of the can is a round hole 11 through which the product 12 to be preserved is introduced into the can Surrounding the hole 11, which may be of any desired size depending upon the nature of the material to be introduced into the can, is an annular flan e 13 extending inwardly from the lower en of the annular wall 14 formed by depressing the center of the head 9 of the can. The depression constituted or bound by the annular wall 14 and the flange 13 may be of any desired shape and size. Preferably, however, it is round and substantially coaxial with the round filling hole 11 located in the center of the head 9.

The closure for closing and sealing the hole 11 when the can has been filled consists of a thin flat piece of metal, preferably a disk 15 slightly larger in diameter than the internal diameter of the depression 16 formed by the annular wall 14. The disk 15 is forced tightly into the depression 16 by a force which causes it to assume a convexo-concave shape during the act of insertion into the depression, as indicated in Figs. 2, 5 and 6, and consequently it will be understood that the joint between the outer edges of the disk 15 and the inner surface of the annular depression 16 engaging the disk is tight and nonleakable.

The method of forming the disk 15 and inserting it into the depression 16 is illustrated in Figs. 8, 4 and 5. In these figures the central portion of the top of the can only is shown and only so much of the apparatus for cutting the disk and forcing it into the depression as is necessary to understand the steps of the method of closing and sealing the can. Inasmuch as the can is filled with the material to be preserved at the time the filling hole is closed and sealed it is most convenient to close and seal the hole while the can is in upright position, and that is the position illustrated. After the can has been filled it passes under a die plate 17 in which is a round opening 18 sli htly larger in diameter than the internal iameter of the depression 16. When the can comes to rest under the die plate the depression 16 is coaxial with the hole 18. On the die plate 17 rests a sheet of metal 19 from which the disk 15 is to be cut. When the can has come to rest a punch 20 alined with the hole 18 descends and cuts a disk 15 from the sheet 19 and pushes it down into the entrance of the depression 16, as indicated in Fig. 4. Thereupon a plunger 21 slidingly mounted in the punch 20 descends and strikes the center of the upper face of the disk 15, forcing it deeper into the depression 16, as indicated in Fig. 5. The lower, disk engaging end of the plunger 21 is enlarged into a head 22, frusto-conical in shape, which when the plunger 21 is inoperative is received within a conical opening 23 formed in the lower end of the punch. The diameter of the lower face of the head 22 of the plunger 21 is substantially smaller than the diameter of the disk 15 and consequently as the plunger forces the disk into the depression 16 the disk is caused to assume the convexo-concave shape indicated in Figs.

5 and 6, so that outwardly acting pressures within the can will not force the disk 15 out of the depression 16. It will be understood that any force acting on the convex side of the disk will first tend to straighten the disk and this act will tend to drive the outer edge of the disk into tighter relation with the inner surfaces of the annular wall 14.

Although the joint established between the outer edges of the disk 15 and the inner surface or sides of the depression 16 by forcing the disk 15 into the depression is tight and non-leakable under great internal pressure in the can, I prefer to insert a bead or fillet of solder 24 into the angle formed between the outer edge of the rim of the disk 15 and the adjacent part or mouth 25 of the depression 16, as illustrated in Fig. 6. Any preferred means may be employed for forming the fillet of solder and in Fig. 6 is shown a rotating soldering iron 26 and a rod of solder 27 which passes through a guide 28. As the soldering iron 26 rotates the rod of solder 27 is brought into contact with the outer surface of its lower end and thereby melted and caused to flow into the angle between the disk 15 and the mouth 25 of the depression.

Having thus described the invention what I claim as new is 1. The method of sealing cans closed at both ends and having a depression in one end and a hole in the depression, which consists in cutting from a thin flat sheet of metal a piece of the same shape as but slightly larger than the depression and then immediately and without interruption forcing the piece of metal into the depression.

2. The method of sealing cans closed at both ends and having a depression in one end with a hole in the depression, which consists in holding a sheet of metal near the de ression, cutting from the sheet a piece 0 the same shape as but slightly larger than the depression, and then forcing the cut piece into the depression.

3. The method of sealing cans closed at both ends and having a round central depression in one of the ends with a hole in the depression, which consists in holding a sheet of metal near the depression, cutting from the sheet a disk of slightly larger diameter than the depression, and then forcing the disk into the depression.

4. The method of sealing cans closed at both ends and having a round depression in one of the ends with a hole in the depression, which consists in holding the can stationary, supporting a sheet of metal opposite the end of the can having the hole therein, cutting from the sheet a disk of slightly larger diameter than the depression, and then forcing the disk into the depression.

5. The method of sealing cans closed at both ends and having a round central depression in one of the ends with a hole in the depression, which consists in holding the can.

in u 'ght position, supporting a sheet of met, a ove the can, cutting from the sheet a disk of slightly larger diameter than the depression, and then forcing the disk into the depression.

6. The method of sealing cans closed at both ends and having a depression in one of the ends with a hole in the depression, which consists in holding the can stationary, supporting a sheet of metal opposite the end of the can having the depresslon therein, cutting from the sheet a wee of the same shape as but slightly larger t an the depression and moving the cut plece by the cutting action toward the depression, and then forcing the piece into the depression.

7. The method of sealing cans closed at both ends and having a central round deression in one of the ends with a hole in the epression, which consists in supporting a sheet of metal opposite the end of the can having the depression therein, cutting from the sheet a disk of slightly larger diameter than the depression and moving the disk toward the depression by the cutting action, and then engaging the center of the disk to force it into the depression so that the act of forcin the disk into the depression will cause t e disk to assume a convexo-concave shape with its concave face outermost.

. 8. The method of sealing cans closed at both ends and having a depression in one of the ends with a hole in the depression, which consists in supporting a sheet of metal opposite the end of the can having the depresslon therein, cutting from the sheet a piece of the same shape as but slightly larger than the depression, forcing the piece into the depression and then soldering the joint between the edges of the piece and the sides of the depression.

JOHN M. MOCLATCHIE. 

